This invention relates to an improved system for draining the used water holding tank of a portable, stand-alone hand-wash sink.
A portable stand-alone sink station, such as described in U.S. Pat. No. 5,687,434, issued Nov. 18, 1997 to Richard Leach Tagg, comprises, in general, a housing which contains a fresh water tank and a used or “grey” water holding tank. One or more sink bowls or basins are mounted above the tanks. Fresh water is periodically supplied to the fresh water tank and the used water is removed. The fresh water is pumped, such as by a conventional foot-operated pump, from the fresh water tank to a faucet or spigot located above each sink bowl. When the user of the sink operates the faucet or spigot, the fresh water pours downwardly into the bowl and, from the bottom of the bowl, into a used water holding tank.
The used water holding tank can hold a little more than the amount of fresh water held in the fresh water tank. Therefore, the used water tank must be emptied when the fresh water tank is replenished or when the water must be removed for maintenance or storage of the sink unit. One way of emptying the used water tank is to provide a normally closed outlet at the bottom of the tank. A service or maintenance person may open the outlet and let the water run out. Typically, when the sink unit is in use, the “grey” may be pumped through a hose from an outlet in the used water tank to a tank truck which can carry the used “grey” water to a suitable disposal site or water treatment plant.
Ordinarily, when the hand-wash station or unit is in use, it is arranged at the location of one or more portable chemical toilets. Thus, the users of the toilets can wash in the sink stations when desired. The portable chemical toilets are typically placed, for example, at construction sites, or sites where crowds gather, such as at public events like parades, sporting events, etc. Similarly, portable sink units may be positioned near these portable chemical toilets for public use.
When portable sink units are to be provided at use sites to enable the units to be lifted easily, they are emptied of water during the transportation to, and the positioning at, the sites where they are used. At that point, the installer or maintenance person fills the fresh water tank. Usually the fresh water for filling is carried by a maintenance truck in a fresh water tank. Thereafter, a maintenance worker periodically may inspect the unit to determine the level of fresh water in the tank and, also, to determine the level of used water held in the unit. At appropriate times, the used water, which fills or substantially fills the used water tank, is drained and the fresh water supply replenished.
Both the fresh water and used water holding tanks must be emptied when the sink units are moved from one use location to another or to a storage location, or to be closed for the winter in locations where the temperature is cold enough to cause the water to freeze. In the past, drain outlets at the bottoms of the tanks provided for such drainage.
In many places, there are objections to or prohibitions against draining the tanks by opening the tank drain outlets and letting the water run out of the tanks upon the adjacent ground. Further, in ordinary use, the service person must be able to maintain the sink unit, that is, replace fresh water, remove used water and replace the items that are used with a sink, such as soap, paper towels, etc., as quickly as possible. Ordinarily, the used water holding tank is emptied by sucking the water out through a pipe connected to a used water tank, through a vacuum system, on the maintenance truck. Filling the fresh water tank is usually accomplished by pumping water into the fresh water holding tank from a water tank on the truck with a long hose. Hence, it is desirable to provide a way to quickly empty the used water tank of the portable sink unit to reduce the time for servicing the units. To simplify emptying and filling the water tank, it is desirable to locate the water drain outlets or parts at one location, preferably at the front of the unit. That simplifies manually connecting water hoses to the service truck.
Thus, this invention is concerned with a system which provides for rapid removal of used water from the grey water holding tanks on portable wash basin stations by the conventional suction or vacuum equipment that is normally carried by portable chemical toilet maintenance vehicles for cleaning portable toilet waste holding tanks.